1. Field of the Invention
The invention relates to an apparatus for skinning fish fillets, comprising a rotatable skinning roller, conveyor means for advancing the fillet to the skinning roller and a skinning knife provided with a cutting edge at a fixed distance from and a presser face equi-spaced from the periphery of the skinning roller.
2. Description of Prior Art
Known apparatus for skinning a fish fillet comprises skinning rollers which are provided on their periphery with a uniform arrangement of teeth in which the faces of the teeth lying in the circumference of the roller are very narrow and the gaps between the teeth relatively large and deep. To improve the running-in or entry of the skin of the leadng fish fillet end under the cutting edge of the skinning knife, according to DE-OS No. 25 23 752 the skinning knife is provided, at its cutting edge, with a surface directed away from and against the rotational direcion of the periphery of the skinning roller.
Such apparatus has a number of advantages: They have a simple construction, the drive for an oscillating skinning knife can be dispensed with and they make the removal of the skin possible without loss of a tip of flesh at the leading end of the fish fillet. However, they also have disadvantages: The yield of fish flesh attainable with such apparatus is not satisfactory because the largest part of the gain in fish flesh attained by the non-loss of the flesh tip at the preceding end of the fish fillet gets lost due to the fact that a thicker layer of fish protein remains on the entire skin surface than is the case with skinning apparatus with a switchable skinning knife. This not only reduces the yield in fish meat, but also impairs the appearance and the consistency of the skinned fish fillets, because maintenance of the silver layer with the protective layer lying thereunder on the skin side of the fish fillet is only attainable with difficulty or is even not obtainable at all. A further important defect of such apparatus is that fillets of fish with thick and/or scaly skin cannot be skinned at all or at least not reliably, while the running-in of the skin below the cutting edge of the skinning knife is not properly attained even with a skinning knife (according to DE-OS No. 25 23 752) provided with a surface directed against the circulating direction of the skinning roller.